Here's why:
* Extraterrestrial invasion: The central conflict revolves around an invasion by Martians, making it a classic example of the alien invasion subgenre within science fiction.
* Technological advancements: The Martians possess advanced technology far beyond anything available to humans at the time of writing, such as heat rays and tripods.
* Social commentary: While not as prominent as in some other science fiction novels, "The War of the Worlds" explores themes of humanity's vulnerability and the potential consequences of technological progress.
While the novel features elements of horror and adventure, its core themes and narrative structure firmly place it within the realm of science fiction.